1. Field of the Invention
This invention relates to connectors for joining panel elements for building modular structures. Anchor members having longitudinally oriented channels are mounted to, or formed integrally on, the edge of panel elements. The base of a connector member is fixedly attached within the channel of a first anchor located on a first panel element. The connector member has a deformable cam section which frictionally engages surfaces within the slot of a second anchor located on a second panel element, thereby securing the first panel to the second panel.
2. Prior Art
Prefabricated panel elements are used to construct modular structures such as partitions, temporary walls, shelves and the like, one example being portable displays for trade shows, etc. The panel elements are usually connected together in an edgewise abutting manner by connectors, such as a snap fittings or couplings, which are mounted to or formed integrally with the panel elements, allowing for quick assembly of the panel elements.
There is a tradeoff between static coupling structures for the panels and movable ones. Static connecting structures may be too tight to make the attachment of the panels smooth and easy, for example when they are new, and/or too loose to provide good structural support after they become worn.
A drawback to many connectors is that they require tools or special implements in order to attach the panel elements together. For example, the panel fasteners may be adjustable such that they can loosely attach panels, and have threaded fasteners, cammed structures or the like which are tightened or deployed after the panels are assembled, using a screwdriver or allen wrench. Tightening threaded fasteners, or tooled operation on another type of connector, is inconvenient and increases the time required to assemble a modular structure. Panel connections without tools are faster and more convenient, for example using connection structures that are inserted into suitable receptacles and lock when the panels are moved relative to one another. However, issues respecting connection tightness versus ease of connection (as well as ease of disconnection) are presented.
Apart from how tight or loose a connecting structure may engage, assembled panels should abut directly without gaps. Structural integrity is improved by direct abutment of the panel edges. Gaps between panels detract from the aesthetic appeal of the structure, for example causing it to appear of a low quality. Some types of connectors include components external to the panel element, which also may be aesthetically objectionable and may interfere with the direct abutment of the panel elements.
A connector structure for the edgewise attachment of panels is disclosed in U.S. Pat. No. 5,531,539--Crawford. Crawford discloses abutting panels with dovetail grooves along their abutting edges. The dovetail grooves on two abutting panels receive the opposite dovetail tenons on the ends of an elongated connector. The panels can be moved relative to one another only parallel to their abutting edges (typically vertically) and horizontal forces that might cause a gap between the panels are opposed by engagement of the tenons in the dovetail slots.
With a connector such as in Crawford, close tolerances are required for the dimensions of the connectors and for the dovetail slots to obtain a tight fit between panels. If the tenons are loose in the slots (i.e., too small), the panel joint is loose and may gap. If the tenons are tight in the slots (i.e., too large), the fastener must be forced to slide in the slot, for example by hammering on the panels. In addition, since the slots extend from one end of the panel to the other (e.g., top to bottom), it is necessary to slide the bottom edge of one past the top edge of the other, or vice versa, to move the fastener into the slot. If the assembled panel elements are to be placed in a tight corner or other restricted space with low clearance, the elongated connector cannot be inserted and the modular structure must be assembled elsewhere before it can be moved into place. Moving the modular structure normally is disadvantageous and may stress the connecting member(s).
Another example of a panel assembly is disclosed in U.S. Pat. No. 4,689,929--Wright. Wright teaches a button type fastener having a small diameter base attached to a first panel and a larger diameter outer button on the base. The larger diameter button is inserted into a slot extending a short distance from the end of a second panel to affix the panels together. The edges of the slot rest on either side of the base. The connection between panels in Wright has the same problems as above. Making such a connector element fit tightly in the slot leads to assembly difficulties, and making it fit loosely detracts from the fit and structural integrity of the assembled panels, particular because the button-type connector is relatively free to move in the slot.
It would be desirable to provide a connector for panel elements which is concealed within the panels, allows for assembly of modular element without tools, maintains successive panels in tight abutment without gaps, and resolves the tradeoff between tightness and looseness without requiring highly accurate dimensional tolerances.